give this a whirl
Code:
{if $smarty.server.HTTPS eq "on"}
<script language="JavaScript" src="https://xxxxxxx.xxx"></script>
[img]https://xxxxxxx.gif[/img]<noscript>[img]https://secure.providesupport.com/image/spacer.gif[/img]</noscript>
{else}
<script language="JavaScript" src="http://xxxxxxx.xxx"></script>
[img]http://xxxxxxx.gif[/img]<noscript>[img]http://providesupport.com/image/spacer.gif[/img]</noscript>
{/if}